Acoustic-electric fusion weight uuv subsea pipeline in-detector positioning and tracking method

Abstract

The application provides a kind of UUV submarine pipeline detector positioning and tracking method of acoustic-electric fusion weight, it is related to underwater target following positioning technical field.First, sensor array is arranged at the bottom of UUV, the physical quantity and UUV state data collected in each sampling period are determined;Then, the environment and signal propagation model is established, the acoustic estimated distance and electromagnetic wave estimated distance of detector and UUV are calculated, and then the acoustic-electric weighted fusion distance of detector relative to UUV is calculated;Again, the acoustic-electric weighted fusion distance is mapped to coordinates;Judge the relative distance trend of detector and UUV, and control the rough following of UUV;Based on the unbalance of acoustic wave and electromagnetic wave in four groups of sensor array, fine attitude control is carried out on UUV;Detect the sudden change of detector working condition and carry out emergency control;The method realizes the comprehensive effect of "full distance accurate positioning, complex environment self-adaptation, sudden state stable response and high-precision following in stable stage".

Description

Technical Field

[0001] This invention relates to the field of underwater target following and positioning technology, and in particular to a method for positioning and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting. Background Technology

[0002] With the rapid development of marine resource development and underwater infrastructure operation and maintenance, unmanned underwater vehicles (UUVs) have become one of the core equipment for underwater operations due to their advantages such as high mobility, wide operating range, and no need for personnel on duty. Among them, the precise tracking and control of UUVs to detectors inside subsea pipelines is a key technology for realizing underwater collaborative operations. The core requirement is to enable UUVs to stably maintain a safe distance from detectors in complex marine environments and adapt to the movement status of detectors in real time, providing support for subsequent data transmission, collaborative detection, and other operations.

[0003] Currently, UUV underwater following and positioning technology mainly relies on single or multi-modal sensor data such as acoustic waves, electromagnetic waves, and optics. Among them, acoustic wave sensors are suitable for medium- and long-range positioning due to relatively small attenuation during underwater propagation; electromagnetic wave sensors (especially extremely low frequency electromagnetic waves) have strong anti-interference capabilities and accurate phase information, making them suitable for short-range high-precision positioning. However, the marine environment is characterized by strong interference and dynamic changes, and underwater detectors may experience jamming, sudden acceleration or deceleration, and other unexpected situations. This places extremely high demands on the positioning accuracy, response speed, and robustness of UUV following algorithms.

[0004] Existing methods for coordinated inspection of subsea pipelines typically employ a combination of "in-pipe detectors + external carriers (such as UUVs or ships)". The in-pipe detector moves with the fluid within the pipeline and records defect data, while the external UUV provides communication relay, positioning reference, and auxiliary monitoring. After searching and analysis, the existing technology most similar to the technical field and core objective of this invention is "UUV underwater target following algorithm based on multi-sensor mean fusion". Its core idea is to collect the target's acoustic signals using multiple sets of acoustic sensors mounted on a UUV, and then achieve positioning through mean fusion.

[0005] Although existing solutions have achieved the basic function of underwater following for UUVs, they have the following shortcomings, making it difficult to meet the high-precision and high-robustness following requirements in complex marine environments, as follows:

[0006] 1. Limited Positioning Accuracy and Environmental Adaptability Due to Lack of Dual-Mode Fusion: Existing solutions rely solely on acoustic sensor data, failing to leverage the advantages of electromagnetic wave sensors. While acoustic sensors offer good far-field positioning performance, they are susceptible to multipath interference in the near field, leading to increased positioning errors. Electromagnetic waves (especially extremely low-frequency electromagnetic waves) possess precise phase information in the near field, compensating for the shortcomings of acoustic sensors. The single-mode positioning approach of existing solutions results in unstable positioning accuracy across the entire range and poor environmental adaptability.

[0007] 2. The positioning weight design does not consider multi-dimensional influencing factors: The mean fusion of the existing scheme does not introduce a multi-dimensional weight adjustment mechanism, and does not consider the influencing factors such as sensor signal quality (e.g., log power attenuation ratio LR), modal advantages (far-field / near-field adaptability), historical positioning stability, and environmental parameters (temperature, salinity), resulting in poor robustness of the fusion result, which is easily interfered with in complex marine environments and has large fluctuations in positioning error.

[0008] 3. Lack of a mechanism to handle unexpected situations with the detector: The existing scheme only assumes that the detector moves at a constant speed and does not consider unexpected situations such as jamming, sudden acceleration or deceleration, or signal loss. When the detector jams, the UUV may collide due to continuous approach; when the detector suddenly accelerates or decelerates, the fixed speed adjustment strategy of the existing scheme cannot adapt quickly and is prone to losing the target.

[0009] 4. Low attitude control accuracy and lack of tiered adjustment logic: Existing solutions only adjust speed and heading based on distance deviation, without designing a tiered attitude adjustment strategy based on sensor signal differences. During the stabilization phase, it is impossible to dynamically adjust the control amplitude according to the degree of deviation, which easily leads to over-adjustment or untimely adjustment, making it difficult to maintain a stable attitude of the UUV directly above the detector.

[0010] In summary, existing solutions are insufficient to meet the needs of UUVs for high-precision and high-robustness follower detectors in complex marine environments due to their single data fusion strategy, lack of dual-modal collaboration, and absence of contingency response mechanisms. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a method for locating and tracking detectors inside UUV subsea pipelines by using acoustic-electric fusion weighting to address the shortcomings of the prior art, thereby realizing the location and tracking of detectors inside UUV subsea pipelines.

[0012] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting, comprising:

[0013] A sensor array is arranged at the bottom of the UUV, and the coordinate system of the detector relative to the UUV, the sensor sampling period, and the physical quantities and UUV state data collected in each sampling period are defined.

[0014] Establish an environmental and signal propagation model to calculate the estimated acoustic and electromagnetic distances between the detector and the UUV;

[0015] Calculate the standard deviation of electromagnetic wave phase, the standard deviation of sound wave estimated distance, and the standard deviation of electromagnetic direction angle;

[0016] Calculate the combined acoustic and electrical confidence level and fusion weight, and then calculate the acoustic and electrical weighted fusion distance of the detector relative to the UUV;

[0017] The acoustic-electric weighted fusion distance of the detector relative to the UUV is mapped to coordinates, and the coordinates of the detector relative to the UUV for acoustic and electrical dual-modal fusion are calculated.

[0018] Determine the trend of the relative distance between the detector and the UUV, and perform coarse following control on the UUV;

[0019] Fine attitude control of UUV is achieved based on the imbalance of acoustic and electromagnetic waves in four sensor arrays.

[0020] Calculate the weighted velocity mutation index and weighted distance mutation index of the detector, as well as the detector's velocity and distance reliability, detect sudden changes in the detector's operating conditions, and implement emergency control.

[0021] Furthermore, the method involves arranging four sensor arrays, each capable of receiving both acoustic and electromagnetic waves, at the bottom of the UUV. Each sensor array includes both acoustic and electromagnetic wave sensors. The coordinate system of the detector relative to the UUV is defined using the UUV's local coordinate system. Wherein, the x-axis points forward along the UUV's heading, the y-axis lies in the horizontal plane and to the right perpendicular to the heading, and the z-axis points towards the water surface; the physical quantities to be collected in the k-th sampling include: the acoustic receiving power of the four sensor arrays simultaneously acquired. Electrical receiving power electromagnetic wave phase difference With the incident azimuth angle of the acoustic array ;

[0022] The collected UUV status data includes UUV travel speed. UUV heading angle UUV roll angle .

[0023] Furthermore, the specific method for establishing the environment and signal propagation model and calculating the acoustic and electromagnetic distance estimations between the detector and the UUV is as follows:

[0024] Step S1: Calculate marine environmental parameters and wave propagation parameters; the marine environmental parameters include electrical conductivity. Wave propagation parameters include sound speed Wavelength of sound waves Sound absorption coefficient Electromagnetic wave wavelength and electromagnetic attenuation coefficient ;

[0025] Step S2: Calculate the acoustic distance between the detector and the UUV based on the acoustic wave propagation model;

[0026] When the UUV does not enter the specified stable following range, calculate the average acoustic power of the four sensor arrays. The effective value of the average sound power is further determined by using the minimum average sound power of the four pre-set sensor arrays. Then calculate the sound wave power attenuation ratio. ;

[0027] Then, based on the sound wave power attenuation ratio, a sound wave propagation model is constructed. The estimated sound wave distance in the sound wave propagation model is then solved iteratively to obtain the estimated sound wave distance between the detector and the UUV:

[0028] Step S3: Calculate the electromagnetic distance between the detector and the UUV based on the extremely low frequency electromagnetic wave propagation model;

[0029] When the UUV does not enter the specified stable tracking range, calculate the average electrical power of the four sensor arrays. The effective value of the average power is further determined by using the minimum average power of the four pre-set sensor arrays. Then calculate the electromagnetic wave power attenuation ratio. ;

[0030] Then, an electromagnetic wave propagation model is constructed based on the electromagnetic wave power attenuation ratio. The electromagnetic wave estimated distance in the electromagnetic wave propagation model is solved iteratively to obtain the electromagnetic wave estimated distance between the detector and the UUV.

[0031] Furthermore, the specific method for calculating the combined acoustic and electrical confidence level and fusion weight, and then calculating the acoustic-electric weighted fusion distance of the detector relative to the UUV, is as follows:

[0032] Calculate the logarithmic power attenuation ratio of sound waves As an indicator of the reliability of acoustic signals;

[0033] Calculate the logarithmic power attenuation ratio of electromagnetic waves As an indicator of the reliability of electromagnetic wave signals;

[0034] The acoustic and electrical logarithmic power attenuation ratios and the LR effectiveness factor are calculated using the Sigmoid mapping. , ;

[0035] Calculate the distance-condition matching factor, including the electromagnetic near-field advantage matching factor and the acoustic mid-to-long-range advantage matching factor;

[0036] Based on the standard deviation of sound wave distance and electromagnetic direction variance Calculate the stability factors of sound waves and electromagnetic waves. , ;

[0037] Using the acoustic and electrical logarithmic power attenuation ratio (LR) effectiveness factor as the dominant factor, and the distance-condition matching factor and stability factor as auxiliary factors, the acoustic and electrical comprehensive confidence level for calculating the actual distance between the detector and the UUV is obtained. , ;

[0038] Based on the combined trust level of acoustic and electrical signals, the acoustic and electrical distance fusion weights are calculated. Furthermore, amplitude limiting is applied to the acoustic and electrical distance fusion weights;

[0039] Then, the acoustic-electric weighted fusion distance of the detector relative to the UUV is calculated. .

[0040] Furthermore, the specific method for mapping the acoustic-electric weighted fusion distance of the detector relative to the UUV into coordinates is as follows:

[0041] Calculate the direction angle of electromagnetic waves and sound waves , Further distance estimation is based on the acoustic waves of the detector relative to the UUV. Estimating distance with electromagnetic waves Calculate the coordinates of the acoustic and electrical single-modal detectors relative to the UUV. ;

[0042] Then calculate the average coordinates of the acoustic and electrical single-mode detectors relative to the UUV. Then, the coordinates of the detector relative to the UUV are calculated. .

[0043] Furthermore, the determination of the relative distance trend between the detector and the UUV, and the coarse following control of the UUV, includes coarse heading control and coarse speed control of the UUV, specifically as follows:

[0044] The target heading angle of the UUV is calculated based on the coordinates of the detector relative to the UUV, which is based on the fusion of acoustic and electronic modes. ;

[0045] Next, calculate the deviation angle of the UUV's heading, and then determine the coarse heading adjustment amount of the UUV before attitude fine-tuning. And a single-step limit is applied to the coarse heading adjustment.

[0046] Based on the average working distance at the kth sampling time Determine the following speed of the UUV And impose constraints on following speed changes.

[0047] Furthermore, the specific method for fine attitude control of the UUV based on the imbalance of acoustic and electromagnetic waves in the four sensor arrays is as follows:

[0048] Calculate the total acoustic power of the four sensor arrays. and total effective sound power Then, the imbalance of acoustic power before and after the four sets of sensor arrays is calculated. and left-right imbalance ;

[0049] Calculate the total electromagnetic power of the four sensor arrays. and total effective electromagnetic wave power Imbalance in electromagnetic wave power Left-right imbalance ;

[0050] Based on the comprehensive trust level of sound and electricity , Calculate the UUV attitude weights for acoustic-electric dual-modal fusion. , ;

[0051] Then, the attitude error of the UUV based on the fusion of acoustic and electronic modes is calculated;

[0052] When the detector is at the acoustic-electric weighted fusion distance relative to the UUV During the stable distance range, fine-tuning of the attitude of the UUV is enabled:

[0053] Calculate the heading fine-tuning angle of the UUV about the z-axis Then calculate the total heading adjustment angle of the UUV. ;

[0054] Calculate the velocity fine-tuning amount of the UUV along the x-direction Then calculate the total speed of the UUV. The adjustment amount of the UUV speed is limited to meet the set conditions, so that the UUV and the detector are within a stable distance range, and the UUV attitude is always adjusted to be directly below the detector, ensuring the optimal detection attitude and stable following of the detector in the pipeline.

[0055] Furthermore, the specific method for calculating the weighted velocity mutation index and weighted distance mutation index of the detector, as well as the detector's velocity, distance reliability, and detecting sudden changes in detector operating conditions and performing emergency control is as follows:

[0056] Step C1: Calculate the detector weighted velocity mutation index;

[0057] Calculate the equivalent estimation speed of the detector ;

[0058] The effective confidence level of the detector in both acoustic and electrical modes is calculated based on the combined confidence level of acoustic and electrical distance fusion weights. Furthermore, the detector velocity reliability weight is calculated based on the effective confidence level and stability factor of the acoustic-electric dual-mode. ;

[0059] Calculate the weighted moving average of the detector velocity Then, the weighted velocity mutation index is calculated. ;

[0060] Step C2: Calculate the detector weighted distance abrupt change index;

[0061] Based on effective confidence of acoustic-electric dual-modal and UUV attitude weights , Calculate distance reliability weights Then, the weighted distance abrupt change index of the four sensor arrays along the pipeline direction is calculated. ;

[0062] Step C3: Determine and control detector blockage;

[0063] In the event window Internal calculation of detector speed, distance reliability and ;

[0064] If the detector's speed, distance reliability, and reliability are all less than the set threshold, then no detector jamming determination will be performed in this window; otherwise, a detector jamming determination will be performed, specifically as follows:

[0065] Calculate the weighted velocity change of the detector ;

[0066] Calculate the weighted distance change of the detector ;

[0067] If both the weighted velocity change and the weighted distance change of the detector meet the preset jamming velocity threshold and jamming distance threshold, the detector is determined to be in a jammed state: Set the detector jamming state event trigger flag. This triggers UUV hovering;

[0068] Step C4: Determine if the detector suddenly accelerates / decelerates;

[0069] In the event window If the detector's speed, distance reliability, and overall reliability are all less than the set thresholds, this window will not perform a sudden acceleration / deceleration check; otherwise, a sudden acceleration / deceleration check will be performed, using the following method:

[0070] Calculate the weighted average velocity change of the detector ;

[0071] Calculate the weighted average distance change of the detector ;

[0072] If the weighted average velocity change and the weighted distance change of the detector satisfy: and If the detector is determined to have suddenly accelerated, the sudden acceleration event trigger flag for the detector is set. ;like and If the detector is determined to have suddenly decelerated, then the sudden deceleration event trigger flag for the detector is set to... ;in, , These are the threshold values ​​for the distance change when the detector suddenly accelerates and decelerates, respectively. , These are the threshold values ​​for the rate change of the detector during sudden acceleration and sudden deceleration, respectively.

[0073] Step C5: Calculate the nominal detector velocity to update the detector velocity, and calculate the UUV command velocity;

[0074] Calculate Event Window Internal detector velocity-weighted average Then, the nominal velocity is calculated to update the detector velocity;

[0075] Calculate the corrected speed when the detector sends an acceleration or deceleration event. ;

[0076] Using speed reliability weights to measure the total speed of UUVs The UUV command speed is obtained by weighted fusion of the corrected speed and the fusion. And apply speed constraints to the speed of UUV commands.

[0077] The beneficial effects of adopting the above technical solution are as follows: The UUV subsea pipeline detector positioning and tracking method with acoustic-electric fusion weighting provided by this invention:

[0078] (1) Achieve stable positioning across the entire range and improve environmental adaptability;

[0079] This invention achieves complementary advantages in far-field and near-field positioning through dual-mode fusion of acoustic waves and extremely low-frequency electromagnetic waves. In far-field scenarios, the acoustic mode is dominant, fully leveraging its advantage of low attenuation over long distances; in near-field scenarios, the extremely low-frequency electromagnetic wave mode is dominant, utilizing its precise phase information and resistance to multipath interference. Combined with dual-mode data fusion optimization, this ensures stable positioning accuracy for the UUV throughout the entire tracking process.

[0080] (2) It enhances the robustness of the positioning fusion results and reduces the impact of environmental interference;

[0081] To address the poor robustness caused by the lack of multi-dimensional consideration in positioning weights, this invention introduces a multi-dimensional weight adjustment mechanism that integrates sensor signal quality (log power attenuation ratio LR), modal scene advantages, historical positioning stability, and environmental parameters, replacing the existing simple mean fusion strategy.

[0082] (3) Covers emergency response to all emergency scenarios, ensuring safe and reliable follow-up operations;

[0083] To address the lack of a mechanism for handling sudden detector conditions, this invention designs identification logic and dedicated emergency response strategies for two core types of sudden conditions: detector jamming and sudden acceleration / deceleration. This significantly improves the safety, continuity, and engineering practicality of follow-up operations.

[0084] (4) Achieve high-precision attitude stability following and improve relative position control accuracy;

[0085] To address the issues of low accuracy and lack of tiered attitude control logic, this invention designs a tiered attitude adjustment strategy based on the difference between multi-sensor signals. Ultimately, this strategy can stably maintain the UUV directly above the detector, meeting the stringent requirements for relative positional stability between the UUV and the detector in underwater collaborative operations.

[0086] The method of this invention comprehensively solves the core pain points of existing UUV following and positioning technologies, and achieves the comprehensive effect of "precise positioning at all distances, adaptive to complex environments, stable response to emergencies, and high-precision following during stable phases", providing reliable technical support for the collaborative operation of underwater UUVs and detectors. Attached Figure Description

[0087] Figure 1 A flowchart of the UUV subsea pipeline detector localization and tracking method with acoustic-electric fusion weighting provided in this embodiment of the invention;

[0088] Figure 2 This is a schematic diagram of signal transmission between the UUV and the detector inside the subsea pipeline after a sensor array is arranged at the bottom of the UUV, as provided in an embodiment of the present invention. Detailed Implementation

[0089] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0090] In this embodiment, the method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting is as follows: Figure 1 As shown, it includes the following steps:

[0091] Step 1: Arrange a sensor array at the bottom of the UUV, such as... Figure 2 As shown, the coordinate system of the detector relative to the UUV, the sensor sampling period, and the physical quantities and UUV state data collected in each sampling period are defined.

[0092] Step 1.1: Arrange a sensor array at the bottom of the UUV;

[0093] Four sensor arrays, each with acoustic and electrical receiving capabilities, are installed at the bottom of the UUV.

[0094] ;

[0095] ;

[0096] In this embodiment, each set of sensors includes a sensor for receiving sound waves and a sensor for receiving electromagnetic waves. The sensor for receiving sound waves is an SQ48-00 spherical hydrophone, and the sensor for receiving electromagnetic waves is an IGGE-80 magnetic field sensor.

[0097] Step 1.2: Define the coordinate system of the detector relative to the UUV and the sampling period of the sensor, and determine the physical quantities and UUV state data to be collected in each sampling period;

[0098] The coordinate system of the detector relative to the UUV is defined using the UUV local coordinate system. The x-axis points forward along the UUV's heading, the y-axis lies in the horizontal plane and points to the right vertically, and the z-axis points towards the water surface (upward is positive).

[0099] Define sensor number The sampling time is Sampling period for:

[0100] ;

[0101] The physical quantities to be collected in the k-th sampling include: the acoustic receiving power of the four sensor arrays collected simultaneously. Electrical receiving power electromagnetic wave phase difference With the incident azimuth angle of the acoustic array ;

[0102] The collected UUV status data includes UUV travel speed. UUV heading angle UUV roll angle ;

[0103] Step 2: Establish an environmental and signal propagation model, and calculate the estimated distance between the detector and the UUV using acoustic and electromagnetic waves;

[0104] Step 2.1: Calculate marine environmental parameters and wave propagation parameters; the marine environmental parameters include electrical conductivity, and the wave propagation parameters include sound speed, sound wavelength, sound absorption coefficient, electromagnetic wavelength, and electromagnetic attenuation coefficient;

[0105] Calculate conductivity :

[0106] ;

[0107] In the formula, For seawater temperature, This refers to seawater salinity.

[0108] Calculate the speed of sound :

[0109] ;

[0110] Calculate the wavelength of sound waves :

[0111] ;

[0112] In the formula, The frequency of the sound wave;

[0113] Calculate the sound absorption coefficient :

[0114] ;

[0115] Calculate the wavelength of electromagnetic waves :

[0116] ;

[0117] Calculate the electromagnetic attenuation coefficient :

[0118] ;

[0119] In the formula The frequency of electromagnetic waves, The speed of light;

[0120] Step 2.2: Calculate the estimated acoustic distance between the detector and the UUV based on the acoustic wave propagation model;

[0121] Step 2.2.1: Calculate the sound wave power attenuation ratio;

[0122] When the UUV does not enter the specified stable following range, calculate the average acoustic power of the four sensor arrays. :

[0123] ;

[0124] in, These are four sets of sound wave power measured by four sensor arrays;

[0125] The effective value of the average sound power is further determined by using the minimum average sound power of four pre-set sensor arrays. :

[0126] ;

[0127] In the formula, The minimum average acoustic power of the four sensor arrays is preset to prevent safety issues caused by abnormal data.

[0128] Further calculation of the sound wave power attenuation ratio :

[0129] ;

[0130] In the formula, This refers to the power of the sound wave emission.

[0131] Step 2.2.2: Calculate the estimated acoustic distance between the detector and the UUV based on the acoustic wave propagation model;

[0132] Constructing a sound wave propagation model:

[0133] ;

[0134] In the formula, Acoustic wave emission gain For sound wave receiving gain, To estimate the distance between the detector and the UUV using acoustic waves;

[0135] For sound wave propagation models, the distance of sound waves is estimated. By performing iterative solutions, the estimated acoustic distance between the detector and the UUV is obtained:

[0136] When the initial iteration n=0:

[0137] ;

[0138] The (n+1)th iteration:

[0139] ;

[0140] The convergence condition for the iteration is: .

[0141] Step 2.3: Calculate the electromagnetic distance between the detector and the UUV based on the extremely low frequency electromagnetic wave propagation model;

[0142] When the UUV does not enter the specified stable tracking range, calculate the average electrical power of the four sensor arrays. :

[0143] ;

[0144] The effective value of the average power is further determined by using the minimum average power value of the four pre-set sensor arrays. :

[0145] ;

[0146] In the formula, A preset minimum power value is used to prevent safety issues caused by abnormal data.

[0147] Calculate the electromagnetic wave power attenuation ratio :

[0148] ;

[0149] The electromagnetic distance between the detector and the UUV is estimated based on the electromagnetic wave propagation model:

[0150] Constructing an electromagnetic wave propagation model:

[0151] ;

[0152] In the formula, For electromagnetic wave emission gain, For electromagnetic wave receiving gain, To estimate the distance between the detector and the UUV's electromagnetic waves;

[0153] For estimating distance using electromagnetic waves in electromagnetic wave propagation models By performing iterative solutions, the estimated electromagnetic distance between the detector and the UUV is obtained:

[0154] When the initial iteration n=0:

[0155] ;

[0156] The (n+1)th iteration:

[0157] ;

[0158] The convergence condition for the iteration is: .

[0159] Step 3: Calculate the standard deviation of the electromagnetic wave phase, the standard deviation of the sound wave estimated distance, and the standard deviation of the electromagnetic direction angle;

[0160] Calculate the standard deviation of electromagnetic wave phase :

[0161] when hour, Set to a number greater than 0 and less than 1;

[0162] when When using the phase angle of electromagnetic waves calculate ;

[0163] when At that time, the phase angle of the electromagnetic wave sampled most recently (5 times) is used. calculate ;

[0164] Calculate the standard deviation of acoustic distance Standard deviation of electromagnetic direction angle :

[0165] when hour, ;

[0166] when At that time, use the most recent Sampling distance estimation With electromagnetic direction angle calculate and ;

[0167] Step 4: Calculate the acoustic and electrical combined confidence level and fusion weight, then calculate the acoustic and electrical weighted fusion distance of the detector relative to the UUV, and calculate the average working distance and distance reference value at different sampling times;

[0168] Step 4.1: Calculate the acoustic and electrical logarithmic power attenuation ratio (LR) effectiveness factor;

[0169] Calculate the logarithmic power attenuation ratio of sound waves As an indicator of the reliability of sound wave signals:

[0170] ;

[0171] Calculate the logarithmic power attenuation ratio of electromagnetic waves As an indicator of the reliability of electromagnetic wave signals:

[0172] ;

[0173] The acoustic and electrical logarithmic power attenuation ratios and the LR effectiveness factor are calculated using the Sigmoid mapping. , :

[0174] ;

[0175] ;

[0176] In the formula, , The Sigmoid center threshold, , The slope is the Sigmoid slope, which is set according to the actual working conditions.

[0177] Step 4.2: Calculate the distance matching factor, including the electromagnetic near-field advantage matching factor and the acoustic mid-to-long-distance advantage matching factor;

[0178] Calculate the electromagnetic near-field dominance matching factor :

[0179] ;

[0180] Calculate the long-range dominance matching factor in acoustic waves :

[0181] ;

[0182] in, For electromagnetic near-field dominant scale, The scales representing the far-field dominance of sound waves are all set according to the operating conditions. This is a distance reference value.

[0183] Step 4.3: Calculate the stability factors of sound waves and electromagnetic waves;

[0184] Based on the standard deviation of sound wave distance and electromagnetic direction variance Calculate the stability factors of sound waves and electromagnetic waves. , :

[0185] ;

[0186] ;

[0187] In the formula, , These are the stability attenuation coefficients for sound waves and electromagnetic waves, respectively, set according to the operating conditions.

[0188] Step 4.4: Calculate the combined trust level of sound and electricity and the fusion weight of sound and electricity distance, and then calculate the weighted fusion distance of sound and electricity;

[0189] Using the acoustic and electrical logarithmic power attenuation ratio (LR) effectiveness factor as the dominant factor, and the distance-condition matching factor and stability factor as auxiliary factors, the acoustic and electrical comprehensive confidence level for calculating the actual distance between the detector and the UUV is obtained. , :

[0190] ;

[0191] ;

[0192] Based on the combined trust level of acoustic and electrical signals, the acoustic and electrical distance fusion weights are calculated. :

[0193] ;

[0194] ;

[0195] In the formula, This is the softmax temperature parameter, set according to the operating conditions.

[0196] Limiting the weights for acoustic and electrical distance fusion:

[0197] ;

[0198] in, , These represent the minimum and maximum values ​​of the distance fusion weights;

[0199] Calculate the acoustic-electric weighted fusion distance of the detector relative to the UUV. :

[0200] ;

[0201] Step 4.5: At the acoustic-electric weighted fusion distance of the detector relative to the UUV Calculate the average working distance at different sampling times based on the above. ;

[0202] Initial sampling time, At that time, the sound and electricity weighted fusion distance was obtained. After: Order ;

[0203] hour:

[0204] ;

[0205] :

[0206] ;

[0207] Further, distance reference values ​​were obtained at different sampling times:

[0208] when hour, ;

[0209] when hour, ;

[0210] Step 5: Map the acoustic-electric weighted fusion distance of the detector relative to the UUV into coordinates;

[0211] Step 5.1: Calculate the direction angles of electromagnetic waves and sound waves. , :

[0212] ;

[0213] ;

[0214] Step 5.2: Calculate the coordinates of the acoustic and electrical single-mode detectors relative to the UUV. : ;

[0215] ;

[0216] ;

[0217] ;

[0218] Step 5.3: Calculate the average coordinates of the acoustic and electrical single-mode detectors relative to the UUV. :

[0219] ;

[0220] ;

[0221] like <5, take =1, N= ,like If ≥5, then N=5;

[0222] Step 5.4: Calculate the coordinates of the detector relative to the UUV for acoustic-electric dual-modal fusion. :

[0223] ;

[0224] ;

[0225] Step 6: Determine the relative distance trend between the detector and the UUV, and perform coarse following control on the UUV;

[0226] Step 6.1: Perform coarse heading control on the UUV;

[0227] The target heading angle of the UUV is calculated based on the coordinates of the detector relative to the UUV, which is based on the fusion of acoustic and electronic modes. :

[0228] ;

[0229] Next, calculate the deviation angle of the UUV's heading:

[0230] ;

[0231] This allows us to determine the coarse heading adjustment amount of the UUV before attitude fine-tuning. :

[0232] ;

[0233] Single-step limit on coarse heading adjustment:

[0234] ;

[0235] Step 6.2: Perform coarse velocity control on the UUV;

[0236] Based on the average working distance at the kth sampling time Determine the following speed of the UUV :

[0237] ;

[0238] Apply constraints to follow speed changes:

[0239] ;

[0240] Step 7: Perform fine attitude control on the UUV based on the imbalance of acoustic and electromagnetic waves in the four sensor arrays.

[0241] Step 7.1: Calculate the imbalance of sound waves and electromagnetic waves in the four sensor arrays;

[0242] Calculate the total acoustic power of the four sensor arrays. and total effective sound power :

[0243] ;

[0244] ;

[0245] In the formula, This is the minimum total acoustic power of the four pre-set sensor arrays.

[0246] Calculate the imbalance of acoustic power before and after the four sensor arrays. :

[0247] ;

[0248] Calculate the left-right imbalance of the acoustic power of the four sensor arrays. :

[0249] ;

[0250] Similarly, calculate the total electromagnetic power of the four sensor arrays. and total effective electromagnetic wave power Imbalance in electromagnetic wave power Left-right imbalance :

[0251] ;

[0252] ;

[0253] ;

[0254] ;

[0255] In the formula, This is the minimum total electromagnetic power of the four pre-set sensor arrays;

[0256] Step 7.2: Calculate the UUV attitude weights and attitude errors based on the acoustic and electrical integrated trust level;

[0257] Based on the comprehensive trust level of sound and electricity , Calculate the UUV attitude weights for acoustic-electric dual-modal fusion. , :

[0258] ;

[0259] ;

[0260] Calculate the attitude error of UUV based on acoustic-electric dual-mode fusion:

[0261] ;

[0262] ;

[0263] when The power received by the four sensor arrays is approximately balanced front to back and left to right, meaning the detector is located directly below the geometric center of the sensor array at the bottom of the UUV.

[0264] Step 7.3: Fine-tune the attitude of the UUV within the stable operating distance range;

[0265] When the detector is at the acoustic-electric weighted fusion distance relative to the UUV Fine-tuning of the attitude of a UUV is enabled when the following conditions are met:

[0266] ;

[0267] In the formula, , These are the lower and upper limits of the stable distance range between the detector and the UUV;

[0268] Calculate the heading fine-tuning angle of the UUV about the z-axis :

[0269] ;

[0270] In the formula, For heading fine-tuning gain;

[0271] Further calculate the total heading adjustment angle of the UUV :

[0272] ;

[0273] Apply a single-step limit to the total heading adjustment angle of the UUV:

[0274] ;

[0275] Calculate the velocity fine-tuning amount of the UUV along the x-direction :

[0276] ;

[0277] Further calculation of the total velocity of the UUV :

[0278] ;

[0279] In the formula, Adjust the gain for speed.

[0280] and satisfy This ensures that the UUV and the detector are within a stable distance range, so that the UUV's attitude is always adjusted to be directly below the detector, guaranteeing the optimal detection attitude and stable following of the detector inside the pipeline.

[0281] Step 8: Detect sudden changes in detector operating conditions and emergency control;

[0282] Step 8.1: Calculate the detector weighted velocity mutation index;

[0283] Calculate the equivalent estimation speed of the detector :

[0284] ;

[0285] The effective confidence level of the detector in both acoustic and electrical modes is calculated based on the combined confidence level of acoustic and electrical distance fusion weights. :

[0286] ;

[0287] Furthermore, the detector velocity reliability weights are calculated based on the effective confidence level and stability factor of the acoustic-electric dual-mode. :

[0288] + ;

[0289] Calculate the weighted moving average of the detector velocity :

[0290] ;

[0291] In the formula, The average forgetting factor is set according to the operating conditions, with an initial value of [value missing]. .

[0292] Calculate the weighted velocity mutation index :

[0293] ;

[0294] Step 8.2: Calculate the detector weighted distance abrupt change index;

[0295] Calculate distance reliability weights :

[0296] ;

[0297] Calculate the weighted distance abrupt change index of the four sensor arrays along the pipeline direction. :

[0298] ;

[0299] Step 8.3: Determine and control detector blockage;

[0300] In the event window Inside, the detector's speed, distance reliability, and... : ;

[0301] If the detector's speed, distance reliability, and other conditions are met:

[0302] ;

[0303] ;

[0304] In the formula, For the reliability and minimum value of the detector;

[0305] In this case, no detector jamming determination will be performed within this window;

[0306] Otherwise, a detector blockage determination is performed, the specific method of which is as follows:

[0307] Calculate the weighted velocity change of the detector :

[0308] ;

[0309] Calculate the weighted distance change of the detector:

[0310] ;

[0311] If the weighted velocity change and weighted distance change of the detector satisfy the following conditions:

[0312] and ;

[0313] In the formula, The pre-set jamming speed threshold, The pre-set blocking distance threshold;

[0314] The detector is then determined to be in a blocked state: Set the detector blocked state event trigger flag. At this point, UUV hovering is triggered, i.e.: ;

[0315] Step 8.4: Determine if the detector suddenly accelerates / decelerates;

[0316] In the event window Within this range, if the detector's speed, distance reliability, and the following conditions are met:

[0317] ;

[0318] ;

[0319] This window will not perform a sudden acceleration / deceleration detection.

[0320] Otherwise, a sudden acceleration / deceleration of the detector is detected, and the specific method is as follows:

[0321] Calculate the weighted average velocity change of the detector :

[0322] ;

[0323] Calculate the weighted average distance change of the detector :

[0324] ;

[0325] If the weighted average velocity change and the weighted distance change of the detector satisfy: and If the detector is determined to have suddenly accelerated, the sudden acceleration event trigger flag for the detector is set. ;like and If the detector is determined to have suddenly decelerated, then the sudden deceleration event trigger flag for the detector is set to... ;in, , These are the threshold values ​​for the distance change when the detector suddenly accelerates and decelerates, respectively. , These are the threshold values ​​for the rate change of the detector during sudden acceleration and sudden deceleration, respectively.

[0326] Step 8.5: Calculate the detector nominal velocity to update the detector velocity, and calculate the UUV command velocity;

[0327] (1) Update detector speed ;

[0328] Calculate Event Window Internal detector velocity-weighted average :

[0329] ;

[0330] Calculate the detector's nominal velocity to update the detector velocity:

[0331] ;

[0332] ;

[0333] in, The nominal speed of the detector, The speed of the detector before the update This is a speed correction factor;

[0334] When a detector jams, the detector speed can be directly adjusted. ;

[0335] (2) Calculate the UUV command speed ;

[0336] Calculate the corrected speed when the detector sends an acceleration or deceleration event. :

[0337] ;

[0338] In the formula, For the preset distance correction gain, The distance to follow the target.

[0339] Using speed reliability weights to measure the total speed of UUVs The UUV command speed is obtained by weighted fusion of the corrected speed and the fusion. :

[0340] ;

[0341] In the formula, The speed control hybrid gain is preset.

[0342] Apply speed constraints to the speed of UUV commands:

[0343] ;

[0344] in, These represent the maximum and minimum speeds of UUV commands;

[0345] Not triggered At that time, take:

[0346] .

[0347] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the present invention.

Claims

1. A method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting, characterized in that, include: A sensor array is arranged at the bottom of the UUV, and the coordinate system of the detector relative to the UUV, the sensor sampling period, and the physical quantities and UUV state data collected in each sampling period are defined. Establish an environmental and signal propagation model to calculate the estimated acoustic and electromagnetic distances between the detector and the UUV; Calculate the standard deviation of electromagnetic wave phase, the standard deviation of sound wave estimated distance, and the standard deviation of electromagnetic direction angle; Calculate the combined acoustic and electrical confidence level and fusion weight, and then calculate the acoustic and electrical weighted fusion distance of the detector relative to the UUV; The acoustic-electric weighted fusion distance of the detector relative to the UUV is mapped to coordinates, and the coordinates of the detector relative to the UUV for acoustic and electrical dual-modal fusion are calculated. Determine the trend of the relative distance between the detector and the UUV, and perform coarse following control on the UUV; Fine attitude control of UUV is achieved based on the imbalance of acoustic and electromagnetic waves in four sensor arrays. Calculate the detector's weighted velocity mutation index and weighted distance mutation index, as well as the detector's velocity and distance reliability, detect sudden changes in detector operating conditions, and implement emergency control.

2. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 1, characterized in that, The method involves arranging four sensor arrays, each capable of receiving sound and electricity, at the bottom of the UUV. Each sensor array includes a sensor for receiving sound waves and a sensor for receiving electromagnetic waves. The coordinate system of the detector relative to the UUV is defined using the UUV local coordinate system. ,in, The axis moves forward along the UUV's heading. The axis is in the horizontal plane and perpendicular to the right. The axis points towards the water surface; the physical quantities to be collected in the k-th sampling include: the acoustic receiving power of the four sensor arrays collected simultaneously. Electrical receiving power electromagnetic wave phase difference With the incident azimuth angle of the acoustic array ; The collected UUV status data includes UUV travel speed. UUV heading angle UUV roll angle .

3. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 2, characterized in that, The specific method for establishing the environment and signal propagation model and calculating the acoustic and electromagnetic distance estimation distances between the detector and the UUV is as follows: Step S1: Calculate marine environmental parameters and wave propagation parameters; the marine environmental parameters include electrical conductivity. Wave propagation parameters include sound speed Wavelength of sound waves Sound absorption coefficient Electromagnetic wave wavelength and electromagnetic attenuation coefficient ; Step S2: Calculate the acoustic distance between the detector and the UUV based on the acoustic wave propagation model; When the UUV does not enter the specified stable following range, calculate the average acoustic power of the four sensor arrays. ; The effective value of the average sound power is further determined by using the minimum average sound power of four pre-set sensor arrays. Then calculate the sound wave power attenuation ratio. ; Then, based on the sound wave power attenuation ratio, a sound wave propagation model is constructed. The estimated sound wave distance in the sound wave propagation model is then solved iteratively to obtain the estimated sound wave distance between the detector and the UUV: Step S3: Calculate the electromagnetic distance between the detector and the UUV based on the extremely low frequency electromagnetic wave propagation model; When the UUV does not enter the specified stable tracking range, calculate the average electrical power of the four sensor arrays. The effective value of the average power is further determined by using the minimum average power of the four pre-set sensor arrays. Then calculate the electromagnetic wave power attenuation ratio. ; Then, an electromagnetic wave propagation model is constructed based on the electromagnetic wave power attenuation ratio. The electromagnetic wave estimated distance in the electromagnetic wave propagation model is solved iteratively to obtain the electromagnetic wave estimated distance between the detector and the UUV.

4. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 3, characterized in that, The specific method for calculating the combined acoustic and electrical confidence level and fusion weight, and then calculating the acoustic-electric weighted fusion distance of the detector relative to the UUV, is as follows: Calculate the logarithmic power attenuation ratio of sound waves As an indicator of the reliability of acoustic signals; Calculate the logarithmic power attenuation ratio of electromagnetic waves As an indicator of the reliability of electromagnetic wave signals; The acoustic and electrical logarithmic power attenuation ratios and the LR effectiveness factor are calculated using the Sigmoid mapping. , ; Calculate the distance-condition matching factor, including the electromagnetic near-field advantage matching factor and the acoustic mid-to-long-range advantage matching factor; Based on the standard deviation of sound wave distance and electromagnetic direction variance Calculate the stability factors of sound waves and electromagnetic waves. , ; Using the acoustic and electrical logarithmic power attenuation ratio (LR) effectiveness factor as the dominant factor, and the distance-condition matching factor and stability factor as auxiliary factors, the acoustic and electrical comprehensive confidence level for calculating the actual distance between the detector and the UUV is obtained. , ; Based on the combined trust level of acoustic and electrical signals, the acoustic and electrical distance fusion weights are calculated. Furthermore, amplitude limiting is applied to the acoustic and electrical distance fusion weights; Then, the acoustic-electric weighted fusion distance of the detector relative to the UUV is calculated. .

5. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 4, characterized in that, The specific method for mapping the acoustic-electric weighted fusion distance of the detector relative to the UUV into coordinates is as follows: Calculate the direction angle of electromagnetic waves and sound waves , Further distance estimation is based on the acoustic waves of the detector relative to the UUV. Estimating distance with electromagnetic waves Calculate the coordinates of the acoustic and electrical single-modal detectors relative to the UUV. ; Then calculate the average coordinates of the acoustic and electrical single-mode detectors relative to the UUV. Then, the coordinates of the detector relative to the UUV are calculated. .

6. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 5, characterized in that, The determination of the relative distance trend between the detector and the UUV, and the coarse following control of the UUV, includes coarse heading control and coarse speed control of the UUV. The specific method is as follows: The target heading angle of the UUV is calculated based on the coordinates of the detector relative to the UUV, which is based on the fusion of acoustic and electronic modes. ; Next, calculate the deviation angle of the UUV's heading, and then determine the coarse heading adjustment amount of the UUV before attitude fine-tuning. And the coarse heading adjustment is limited in one step; Based on the average working distance at the kth sampling time Determine the following speed of the UUV And impose constraints on following speed changes.

7. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 6, characterized in that, The specific method for fine attitude control of UUV based on the imbalance of acoustic and electromagnetic waves in four sensor arrays is as follows: Calculate the total acoustic power of the four sensor arrays. and total effective sound power Then, the imbalance of acoustic power before and after the four sets of sensor arrays is calculated. and left-right imbalance ; Calculate the total electromagnetic power of the four sensor arrays. and total effective electromagnetic wave power Imbalance in electromagnetic wave power Left-right imbalance ; Based on the comprehensive trust level of sound and electricity , Calculate the UUV attitude weights for acoustic-electric dual-modal fusion. , ; Then, the attitude error of the UUV based on the fusion of acoustic and electronic modes is calculated; When the detector is at the acoustic-electric weighted fusion distance relative to the UUV During the stable distance range, fine-tuning of the attitude of the UUV is enabled: Calculate the heading fine-tuning angle of the UUV about the z-axis Then calculate the total heading adjustment angle of the UUV. ; Calculate the velocity fine-tuning amount of the UUV along the x-direction Then calculate the total speed of the UUV. The adjustment amount of the UUV speed is limited to meet the set conditions, so that the UUV and the detector are within a stable distance range, and the UUV attitude is always adjusted to be directly below the detector, ensuring the optimal detection attitude and stable following of the detector in the pipeline.

8. The method for locating and tracking detectors inside UUV subsea pipelines using acoustic-electric fusion weighting according to claim 7, characterized in that, The specific method for calculating the weighted velocity mutation index and weighted distance mutation index of the detector, as well as the detector's speed, distance reliability, and detecting sudden changes in the detector's operating conditions and implementing emergency control is as follows: Step C1: Calculate the detector weighted velocity mutation index; Calculate the equivalent estimation speed of the detector ; The effective confidence level of the detector in both acoustic and electrical modes is calculated based on the combined confidence level of acoustic and electrical distance fusion weights. Furthermore, the detector velocity reliability weight is calculated based on the effective confidence level and stability factor of the acoustic-electric dual-mode. ; Calculate the weighted moving average of the detector velocity Then, the weighted velocity mutation index is calculated. ; Step C2: Calculate the detector weighted distance abrupt change index; Based on effective confidence of acoustic-electric dual-modal and UUV attitude weights , Calculate distance reliability weights Then, the weighted distance abrupt change index of the four sensor arrays along the pipeline direction is calculated. ; Step C3: Determine and control detector blockage; In the event window Internal calculation of detector speed, distance reliability and ; If the detector's speed, distance reliability, and reliability are all less than the set threshold, then no detector jamming determination will be performed in this window; otherwise, a detector jamming determination will be performed, specifically as follows: Calculate the weighted velocity change of the detector ; Calculate the weighted distance change of the detector ; If both the weighted velocity change and the weighted distance change of the detector meet the preset jamming velocity threshold and jamming distance threshold, the detector is determined to be in a jammed state: Set the detector jamming state event trigger flag. This triggers UUV hovering; Step C4: Determine if the detector suddenly accelerates / decelerates; In the event window If the detector's speed, distance reliability, and overall reliability are all less than the set thresholds, this window will not perform a sudden acceleration / deceleration check; otherwise, a sudden acceleration / deceleration check will be performed, using the following method: Calculate the weighted average velocity change of the detector ; Calculate the weighted average distance change of the detector ; If the weighted average velocity change and the weighted distance change of the detector satisfy: and If the detector is determined to have suddenly accelerated, the sudden acceleration event trigger flag for the detector is set. ;like and If the detector is determined to have suddenly decelerated, then the sudden deceleration event trigger flag for the detector is set to... ;in, , These are the threshold values ​​for the distance change when the detector suddenly accelerates and decelerates, respectively. , These are the threshold values ​​for the rate change of the detector during sudden acceleration and sudden deceleration, respectively. Step C5: Calculate the nominal detector velocity to update the detector velocity, and calculate the UUV command velocity; Calculate Event Window Internal detector velocity-weighted average Then, the nominal velocity is calculated to update the detector velocity; Calculate the corrected speed when the detector sends an acceleration or deceleration event. ; Using speed reliability weights to measure the total speed of UUVs The UUV command speed is obtained by weighted fusion of the corrected speed and the fusion. And apply speed constraints to the speed of UUV commands.

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